这很简单：

import SwiftUI
import UserNotifications

@main
struct RSApp: App {
    let center = UNUserNotificationCenter.current()
    
    init() {
        registerForNotification()
    }
    
    func registerForNotification() {
        //For device token and push notifications.
        UIApplication.shared.registerForRemoteNotifications()
        
        let center : UNUserNotificationCenter = UNUserNotificationCenter.current()
        //        center.delegate = self
        
        center.requestAuthorization(options: [.sound , .alert , .badge ], completionHandler: { (granted, error) in
            if ((error != nil)) { UIApplication.shared.registerForRemoteNotifications() }
            else {
                
            }
        })
    }
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

在您的情况下，您正在修改应用程序根视图。因此，您可以将您的代码放入init或onAppear。我建议使用后者（onAppear）只是为了遵循最佳实践。SwiftUI立即创建所有视图，甚至导航链接的目标视图，这意味着初始化器会立即运行。而放在onAppear修饰符中的代码只有在视图显示时才被调用。所以你的代码看起来像这样：

import SwiftUI

@main
struct RSApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
            .onAppear() {
                let center = UNUserNotificationCenter.current()
                center.requestAuthorization(options: [.alert, .sound, .badge]) { success, error in
                    if let error = error {
                        // Handle the error here.
                    }
                    // Enable or disable features based on the authorization.
                }
            }
        }
    }
}